Roll Dart SDK from 4bd4c2a493e9 to 4740b09e11d4 (2 revisions) (#24323)

DEPS

@@ -35,7 +35,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '4bd4c2a493e964e9f7906d0545efa9d57f1d82c3',
+  'dart_revision': '4740b09e11d4dcbc4dbf4ae5a6ce1308418a09db',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_third_party

-Signature: ff3dbf71721820821b74eb3c691ca38a
+Signature: 012b964406f7fb58d8674a197bceeb88
 
 UNUSED LICENSES: